I've got a VHF tuned antenna currently mounted through the back deck of the car near the rear windshield (not touching). I've found it very difficult to find a trunk lip mount from some of the canadian providers....how do those mount? do they drill right through the trunk or?

How much better performance would i get if i were to mount a trunk lip vs the back deck of inside the car (receiving 150-174mhz)

Here's one found using a Google search that mounts to the trunk lip (probably why it's called a trunk lip mount). You loosen the two set screws on the mount. Slide it onto your trunk and tighten the set screws to hold it secure. This provides a standard NMO mount for your antenna so many standard antennas can be used as desired. Just make sure you have good clearance so the mount doesn't rub against the car when opening and shutting the trunk.

Larsen also makes an "L Bracket" mount (TMB-34 [LAR-TMB34] - $7.00 : Radioworld) that you screw into your car's quarterpanel in the trunk or hood area and install a standard NMO mount into the bracket. You can then use any standard NMO mount antenna on this as well.

Either solution works rather well and which you use would depend on your particular situation. The L-Bracket does require some small screw holes while the Trunk Lip mount requires no holes, but generally there's some minor paint damage from the set screws. The damage from both types are minor and easy to touch up.

looks like the L bracket installs by screwing into the inside of the trunk and then allows for it to hang over the edge of the quarterpanel.....ive also found on durham radio a 25 dollar scanner antenna with a mini magmount which might work too thats removable.....

What differences between an 'inside' antenna and an 'outside' antenna? That ranges between a lot and no difference at all. Just depends on how much attenuation there may be in what's between the antenna and the source of the signal. (Really a 'definite' answer, huh?)
There are a number of possible mounts and ways of mounting antennas. I'd suggest taking a look at -all- of them before deciding which would be best for your situation (another 'easy' and 'exact' answer, huh?).
- 'Doc

(If you ever find one of those 'exact' answers that works in all situations, I really wish you'd tell me what it is! I can certainly use one...)